1. Field of the Invention
The present invention relates to a manufacturing method of a substrate, a manufacturing method of a wiring substrate, a glass substrate and a wiring substrate.
2. Description of the Related Art
In recent years, with respect to a wiring substrate mounted with electronic components such as MEMS (Micro Electro Mechanical System), there is a demand for enabling high-density mounting of electronic components and so on with ensuring connection reliability. In response to this demand, the present inventors have proposed that by using, not a resin substrate, a glass substrate which has good properties such as smoothness, hardness, insulation and heat resistance as a core substrate and by filling with metal a through-hole communicating with a front surface and a rear surface of the glass substrate, conduction of each electrical wiring formed on the front and rear surfaces of the substrate can be surely ensured; thereby making it possible to respond to finer wiring, higher density and so on (for example, referring to patent document 1).
The wiring substrate composed of such glass substrate is manufactured by the following procedure. Specifically, as described in, for example, the patent document 1, a step of filling the through-hole with metal by plating method is performed after performing a step of forming the through-hole on the glass substrate. Then, in the earlier stage of the step of filling the through-hole with metal, either one of the two opening parts of the through-hole formed on the front and rear surfaces of the glass substrate is sealed with metal, after that, by depositing metal on the bottom of the sealed hole from the opening part side and by growing metal toward the opening part; the through-hole is filled with metal.
Patent document 1: WO2005/027605